Well done. It is surprising that you haven´t used any epoxy resin. It would have made the boat walls more "plastic", but would have increased expense as well (which somehow would defeat the purpose of using paper to begin with...). Obviously you have been watching other cardboard boats before going on --the inspiration shows-- and you have improved upon them, but I am also surprised that you --or the other guys who built paper boats-- do not treat cardboard the same way plywood is treated; i.e. you guys do not design paper boats with the same criteria used for plywood boats. Namely, I have the Six-Hour canoe or the www.bateau.com plans in mind, which are very simple designs out of plywood. Generally speaking, what you do with plywood you could do with cardboard, so I don´t see a reason not to design a more rounded, a more hydrodinamic boat out of cardboard instead of having those sharp angles and edges. You might be the guy to lead the way.... All the best and, again, congratulations.